[libcamera-devel] [PATCH 2/2] libcamera: camera: Unmap buffers before release

[Laurent Pinchart]

Hi Kieran,

Thank you for the patch.

On Mon, Mar 04, 2019 at 11:25:30PM +0000, Kieran Bingham wrote:
> Before buffers can be released back to V4L2 all mappings must be unmapped.

I don't think "released back to v4L2" is the right terminology. Maybe
"Before buffers can be freed by the V4L2 device that has allocated them,
all mappings must be destroyed" ? Same for the comment below. Apart from
that,

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> Ensure that buffers are released correctly by destroying the buffer pool
> contents before freeing the resources on the stream.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
>  src/libcamera/camera.cpp | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index 8e17085bfb50..875e1e46c89c 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -488,8 +488,13 @@ int Camera::freeBuffers()
>  		if (!stream->bufferPool().count())
>  			continue;
>  
> -		pipe_->freeBuffers(this, stream);
> +		/*
> +		 * Destroy Buffers will empty the pool, and unmap any existing
> +		 * memory mapping. This needs to be done before releasing
> +		 * buffers back to the V4L2Device through freeBuffers().
> +		 */
>  		stream->bufferPool().destroyBuffers();
> +		pipe_->freeBuffers(this, stream);
>  	}
>  
>  	state_ = CameraConfigured;

-- 
Regards,

Laurent Pinchart